Lighting modules of the type mentioned in the introduction are known, in which light emitted by light emitting diodes is guided by means of a solid optical waveguide, for example an optical waveguide made of plexiglass, to a light sensor in order to sense a brightness and/or color of the light emitted by the light emitting diodes, for example. The measured values can be used, for example, to control the light emitting diodes in order to control brightness by suppressing brightness fluctuations, for example. However, manufacture of the solid optical waveguide involves costs, and assembly of the lighting module is also more complicated on account of the presence of the solid optical waveguide.